There will be two treatment cohorts in this study, each comprised of 40 randomized (1:1 active to placebo) and treated patients (adults ≥18 and children ≥12 years of age). In Cohort 1, patients will be enrolled and randomized to receive the 32 mg dose of AeroVanc bid or placebo bid. Prior to starting enrollment in Cohort 2, a safety evaluation will be carried out by the Data Monitoring Committee (DMC) based on treatment data from the first 20 patients in Cohort 1. Subject to the Sponsor's written communication of the DMC's opinion of acceptable safety, the dose for the active arm in Cohort 2 will be escalated to 64 mg bid. Optionally, the active arm for Cohort 2 may also be kept the same (32 mg bid), or reduced to 16 mg bid, depending on the outcome of the DMC's safety evaluation.